Clock



FIG. 1 is a front perspective view of a clock showing my new design;

FIG. 2 is a typical side elevational view thereof;

FIG. 3 is a typical plan view thereof;

FIG. 4 is a front perspective view of a second embodiment of my new design of FIGS. 1-3;

FIG. 5 is a front perspective view of a third embodiment of my new design of FIGS. 1-3. 

The ornamental design for a clock, substantially as shown. 